901- Petition for Writ of Mandate - Judge/Commissioner
California Constitution Art. 6 Sect. 21 gives you the right to a judge [appointed by the Governor] as opposed to Commissioner [hired by the courthouse] or judge pro tem [lawyer playing judge for the day]. You filed papers that said you did not "stipulate" [=agree to] a commissioner or judge pro tem, so only a judge should have made the recent decision addressed here.
You also have the right to exclude at least one judge from hearing your case under CCP 170.6, called a "peremptory challenge," also using the slang "papering" the judge. This means that the judge you identified has no authority to make any decision in your case, and can only pass it on to different judge.
In your case, the judge or commissioner made a decision in your case, anyway. Usually, that is because they denied your motion or otherwise ruled without even reading your papers or checking to see that you excluded them. That ignorance to your papers is obviously one of the reasons why we excluded them. When they do this, your remedy is to file this Petition, to have the Appellate court order the cancellation of that order and to reset the hearing in front of different judge. It is almost always granted, which makes the case go back two spaces on the game board and reset the same hearing after the Appellate court rules.
You have the right to refuse to have a Commissioner hear your case, and have a judge instead. You also have the right to exclude one judge because he/she may be biased against tenants or you. You also have the right to exclude a judge because of a specific showing of bias. They are supposed to respect those rights and hand the case to a different judge. However, when they are really biased and corrupt, they refuse to follow the law and constitution they swore to uphold in order to get their esteemed position. That's when you have to ask the Appellate Department of the court to intervene. You only have 10 days to file this petition from the time of the ruling.
This Petition is to ask the appellate court to stop the case and undo what the judge or commissioner did, putting you back where you should have been, in front of a different judge. Usually, they grant these petitions, and sometimes they not only stop the case but take their time in ruling on the petition, so as to signal to the commissioner or judge that they hurt the landlord they were bending over backwards to help. It might delay the eviction case for 2-4 months, only to have the whole decision by the trial court vacated.